Daisy-Chain Connector Circuit With Automatic Termination Switching

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Solution Overview

Problem

Existing communication systems with daisy-chain connections require multiple termination resistors and complex control mechanisms to function correctly, leading to inefficiencies and incorrect operation when a device is positioned at the termination or middle of the chain.

Innovation Solution

A communication system with a single termination resistor that automatically switches its connection state based on the device's position in the daisy-chain, using a valid/invalid switching circuit and control signals to ensure proper functioning as either a termination or middle device, regardless of connector attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple termination resistors are used in daisy-chain connected communication devices, then the communication reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvecommunication reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic termination resistor configuration where each communication device can automatically adjust its termination resistor connection state based on its position in the daisy-chain. The control circuit detects whether the device is at the termination end or middle position and dynamically connects or disconnects the internal termination resistor accordingly, eliminating the need for multiple fixed termination resistors while maintaining communication reliability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The communication device performs self-diagnosis of its position in the daisy-chain through the control circuit, which automatically determines whether it is positioned at the termination end or middle based on connection status. This self-service mechanism enables the device to autonomously configure its termination resistor without external intervention, simplifying the overall system while ensuring proper termination at all times

Inventive Principle:
Principle #25Self-service

2Object-affected harmful factors

If a communication device includes an internal termination resistor, then the signal reflection is reduced, but the ease of operation decreases due to the need to switch the resistor connection state

Engineering Contradiction:
Improvesignal reflectionVSAvoidease of operation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The control circuit automatically detects the device's position in the daisy-chain and autonomously controls the switching element to connect or disconnect the termination resistor as needed. This self-service operation eliminates the need for manual configuration by users, making the system easy to operate while maintaining optimal signal termination to reduce reflection

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control circuit continuously monitors the connection status of communication cables and provides feedback to the switching element. Based on this feedback, the system automatically adjusts the termination resistor connection state to match the current daisy-chain configuration, ensuring minimal signal reflection without requiring user intervention

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If the termination resistor connection is manually controlled, then the manufacturing precision is improved, but the productivity decreases

Engineering Contradiction:
Improveconnection precisionVSAvoidproductivity
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system performs automatic position detection and termination resistor configuration through the control circuit, eliminating manual intervention entirely. The control circuit autonomously determines the device's position in the daisy-chain and adjusts the termination resistor connection accordingly, achieving both high precision in termination configuration and high productivity through automated operation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control circuit is pre-configured with the logic to detect device position and control the switching element appropriately. This preliminary setup enables the system to automatically and immediately adjust termination resistor connections when devices are added or removed from the daisy-chain, ensuring precise termination configuration without manual intervention and maintaining high system productivity

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4235445B1Communication system
Publication Date: 2024.10.30 KAWASAKI JUKOGYO KK
  • EP4235445B1 patent drawingFigure 1
  • EP4235445B1 patent drawingFigure 2

AI summary

In a communication system of the present invention, first and second device-side connectors (21A, 21B) and first and second cable-side connectors (31A, 31B) are configured such that, when the first device-side connector (21A) and the first cable-side connector (31A) are connected to each other, a communication line connection portion (22) of the first device-side connector (21) and a communication line connection portion (32) of the first cable-side connector (31A) are connected to each other, and when the second device-side connector (21B) and the second cable-side connector (31B) are connected to each other, a communication line connection portion (22) of the second device-side connector (31B) and a communication line connection portion (32) of the second cable-side connector are connected to each other, and a valid/invalid switching circuit (5) is configured to: in a case where the first and second cable-side connectors (31A, 31B) are connected to the first and second device-side connectors (21A, 21B), respectively, render a connection of a termination resistor (4) to a pair of conductors of an internal communication line (3) invalid; and in other cases, render the connection of the termination resistor (4) to the pair of conductors of the internal communication line (3) valid.